كتاب العين

Al-Ain dictionary is the first coordinated dictionary of the Arabic language. It was written by Al-Khalil bin Ahmed Al-Farahidi and completed and arranged by Al-Laith bin Al-Muzaffar Al-Laithi Al-Kinani. It relies in its arrangement on the exits of the letters from the deepest point in the throat, through the movements of the tongue and up to the edges of the lips. Then the hollow vowels follow them